Testosterone replacement therapy can increase circulating endothelial progenitor cell number in men with late onset hypogonadism

Abstract

SUMMARYCirculating endothelial progenitor cells (EPCs) are bone marrow-derived cells required for endothelial repair. A low EPC number can be considered as an independent predictor of endothelial dysfunction and future cardiovascular events. Recent evidence shows that patients with hypogonadal symptoms without other confounding risk factors have a low number of circulating progenitor cells (PCs) and EPCs, thus highlighting the role of testosterone in the proliferation and differentiation of EPCs. Here, we investigate if testosterone replacement therapy (TRT) can increase circulating EPC number in men with late onset hypogonadism. Forty-six men (age range, 40-73 years; mean age, 58.3 years) with hypogonadal symptoms were recruited, and 29 men with serum total testosterone (TT) levels less than 350 ng/dL received TRT using transdermal testosterone gel (Androgel; 1% testosterone at 5 g/day) for 12 months. Circulating EPC numbers (per 100 000 monocytes) were calculated using flow cytometry. There was no significant association between serum TT levels and the number of circulating EPCs before TRT. Compared with the number of mean circulating EPCs at baseline (9.5 AE 6.2), the number was significantly higher after 3 months (16.6 AE 11.1, p = 0.027), 6 months (20.3 AE 15.3, p = 0.006) and 12 months (27.2 AE 15.5, p = 0.017) of TRT. Thus, we conclude that serum TT levels before TRT are not significantly associated with the number of circulating EPCs in men with late onset hypogonadism. However, TRT can increase the number of circulating EPCs, which implies the benefit of TRT on endothelial function in hypogonadal men.

Restoration of erectile function with intracavernous injections of endothelial progenitor cells after bilateral cavernous nerve injury in rats

“…Moreover, PDE5 inhibitors play an indirect role in vascular regenerative therapy for ED by facilitating EPC release from bone marrow and through their transdifferentiation in the peripheral blood (Foresta et al ., ; La Vignera et al ., ). Furthermore, testosterone replacement therapy can increase the number of circulating EPCs and improve erectile function in hypogonadal men (Liao et al ., ). Mobilization of EPCs from bone marrow has also been considered as a possible mechanism in the chronic administration of melatonin for the prevention of ED in diabetic rats (Qiu et al ., ).…”

Comprehensive evaluation of androgen replacement therapy in aging Japanese men with late-onset hypogonadism

“…LOH-related hypogonadal symptoms include decreased muscle mass and strength, decreased bone mass and osteoporosis, increased central body fat, decreased libido and sexual desire, forgetfulness, loss of memory, difficulty in concentration, insomnia and a decreased sense of well-being [7]. LOH may be associated with a significant deterioration in health-related quality of life (HRQOL) and many adversely affect the function of multiple organ systems.…”

Testosterone level and endothelial dysfunction in patients with vasculogenic erectile dysfunction

“…On the contrary, other study had investigated the effect of TRT on the number of circulating EPCs in hypogonadal patients, the results showed that post-TRT, T levels and EPC numbers had increased significantly compared with the baseline level in which T level had no significant association with the number of circulating EPCs (Liao et al, 2013) (Table 5). Using of CD131, VEGFR2 in the CD34 triple-positive cells by the dual expression may signify a true limitation of this study in which the number of EPCs calculated by this dual marker will be much less than the actual number.…”